A gas turbine engine generally includes, in serial flow order, an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air enters the inlet section and flows to the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel mixes with the compressed air and burns within the combustion section, thereby creating combustion gases. The combustion gases flow from the combustion section through a hot gas path defined within the turbine section and then exit the turbine section via the exhaust section.
In particular configurations, the compressor section includes, in serial flow order, a low pressure compressor (“LP compressor”) and a high pressure compressor (“HP compressor”). The LP compressor and the HP compressor may include one or more axially spaced apart stages. Each stage may include a row of circumferentially spaced apart stator vanes and a row of circumferentially spaced apart rotor blades positioned downstream of the row of stator vanes. The stator vanes direct the air flowing through the compressor section onto the rotor blades, which impart kinetic energy into the air to increase the pressure thereof.
In general, it is desirable for gas turbine engines to have a high overall pressure ratio (“OPR”), the ratio of the stagnation pressure at the front and the rear of the compressor section. Typically, a higher OPR is indicative of higher gas turbine efficiency. High OPRs, however, result in high compressor discharge temperatures and high temperatures in the aft or downstream stages of the compressor section.
The rotor blades may be constructed from materials that limit the OPR of the gas turbine engine. That is, the material properties of the rotor blades limit the temperatures that the compressor may experience. In this respect, the material properties of the rotor blades may hinder the efficiency of the gas turbine engine. Accordingly, a gas turbine engine having a cooling circuit that permits increased compressor temperatures would be welcomed in the technology.